Solid state microwave oscillators are used as sensors, communication sources, and measuring instruments in a wide variety of applications, such as, for example, radio communications, military and commercial radar sources, anti-lock brakes, airborne collision avoidance radar, traffic flow monitoring, automatic traffic gates, process control equipment, alarms, train derailment sensors, vibration detectors, tachometers, and moisture content monitors, to name just a few. The use of sensors has become prevalent in every day use and throughout the industry. For example, thin film magnetic sensors are used in military or consumer applications and they use Hall effect, magneto-resistance (CMR) effect, or giant-resistance (GMR) effect.